/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.flink.ml.cluster.statemachine.event;

/**
 * abstract state machine event.
 * @param <TYPE> event type
 */
public abstract class AbstractEvent<TYPE extends Enum<TYPE>>
		implements Event<TYPE> {

	private final TYPE type;
	private final long timestamp;

	// use this if you DON'T care about the timestamp
	public AbstractEvent(TYPE type) {
		this.type = type;
		// We're not generating a real timestamp here.  It's too expensive.
		timestamp = -1L;
	}

	// use this if you care about the timestamp
	public AbstractEvent(TYPE type, long timestamp) {
		this.type = type;
		this.timestamp = timestamp;
	}

	/**
	 * @return event timestamp
	 */
	@Override
	public long getTimestamp() {
		return timestamp;
	}

	/**
	 * @return event type.
	 */
	@Override
	public TYPE getType() {
		return type;
	}

	@Override
	public String toString() {
		return "EventType: " + getType();
	}
}
